Villagers thought him gentle and kind; and one generous act stood out above the rest. In his twenties, Wu Huanming took in a young disabled boy he found on the streets.

"The child was always warmly and newly dressed; any time he caught a cold Wu would rush him to the doctor. He took great care of him, but when people asked why, he just said the kid brought him luck," said a neighbour.

But yesterday morning this tender-hearted man hacked to death seven kindergarten pupils, their teacher and her mother, wounding 11 more three- to six-year-olds. The assault in Lincheng village, Hanzhong, in north-western Shaanxi province, would horrify any community. It is all the more shocking because it is China's fifth such attack on young children since late March. In all, 15 have been killed and 60 injured.

That this attacker was successful and well-liked makes it all the more incomprehensible. That many of his victims were their parents' only children, thanks to China's birth control policies, underscores its cruelty. In minutes he destroyed the centre of his friends' and neighbours' lives.

"They were so young and innocent," said one shocked mother, as her "active, outgoing" daughter lay unconscious in a hospital bed. "We still don't know how serious the injuries are and fear she will suffer lasting trauma. How will she be able to spend the rest of her life?"

Wu knew the little girl, as he did many of his victims; the family considered him a friend and he often dropped in to chat. Now they feel only hatred.

"If he was still alive we would all have used our knives to hack at him, one by one, until he too was dead," her grandmother said.

The trigger for his violence appears banal: a property dispute. Wu, 48, had rented a house next to the kindergarten and wanted it to move out when the lease expired in April. Wu Hongying, the teacher, wanted to stay until summer.

The disagreement erupted into an open row this week. Too scared to intervene, neighbours shut their doors when Wu ran back to his house and grabbed a meat cleaver. Tall and powerfully built, he quickly overcame the 50-year-old teacher and attacked her 80-year-old mother. Then, raining blow after blow upon their heads, he wounded or killed every child attending class that day. Most seem to have been rooted to the spot in shock. One little boy, despite his injuries, escaped to raise the alarm.

Villagers said their legs buckled when they entered the blood-soaked kindergarten room. Children lay motionless upon or underneath desks. Another was slumped by the door, with a long, inch-wide wound across her scalp.

By then, Wu had returned home. His cousin has reported seeing the killer standing on his balcony, smoking a cigarette as he watched villagers rush to rescue the children. Then he went inside and killed himself. Officials have responded to the epidemic of violence in China with high profile security measures. In Changsha, Hunan province, police officers with submachine guns are reportedly guarding some kindergartens. Chongqing has pledged to spend 1.2bn yuan (£120m) on extra police patrols and security guards.

Hanzhong had stationed 2,000 extra police officers and guards around the city's schools two days before Wu's attack; the kindergarten, small and privately run, appears to have been unprotected. Police have since set up roadblocks round the village and residents reported patrols through the night. There is a heavy police presence outside the hospitals treating injured children.

Some journalists in the area were followed or stopped and relatives said they had been ordered not to speak to reporters. Though some talked to the Guardian, none would be identified. At one hospital an official interrupted a man's description of his grandson with the order: "Don't tell them anything."

Domestic media coverage relating to recent attacks has given minimal detail of incidents, instead focusing on preventive measures. There is undoubtedly real concern that reports will spark further copycat assaults. But many experts argue that must be balanced with the public's right to know; several Hanzhong residents were unaware of the recent attacks. Others believe more open discussion would help to ensure security measures are matched by efforts to address underlying causes.

"It's not that [China's leaders] are immune or unconcerned or not in anguish. I think it has to do with trying to figure out what they need to do about it," said Russell Leigh Moses, a Beijing-based political analyst, of the government's focus on protecting schools.

Some experts have pointed to the desperate need to improve awareness of and treatment for mental illness in China. Others warn that rocketing inequality, allied to massive social change, is leaving many citizens bewildered and alienated. But though Lincheng is poor — many from the village become migrant workers, with several parents travelling hundreds of miles to their children's bedsides this week — Wu was one of Lincheng's wealthiest residents. Unlike other recent attackers, portrayed as unsuccessful loners, the tree merchant had a wife and family; his biological son is now a university student.

Last month he told a villager that he had become ill and could no longer work; there are rumours he had cancer and believed it terminal. He had complained of sleeplessness and a relative, Wu Huangcheng, told Reuters that he had been "talking nonsense … like he was unbalanced." He had no history of mental problems. Perhaps there are no real explanations for Wu's act.

At one hospital red-eyed parents leapt to their feet for a glimpse as orderlies pushed three victims from surgery to intensive care. The children's heads, though doubled in size by thick bandages, were tiny upon the pillows. A little hand fell limply from beneath a blanket.

The suffering of children brings anguish anywhere. But in China they are particularly precious because of the importance of continuing family lines, said experts. "Children are the most important part of the family because the one-child policy is so strict these days," added one survivor's grandmother.

In Lincheng family planning injunctions are painted upon the walls. One includes the government promise: "Children will be happy all their lives."